1. Field of the Invention
The present invention relates to an absorbent article for absorbing and retaining a liquid waste such as menstrual blood and, more particularly, to an absorbent article having leakage preventing side walls on the two widthwise sides of the liquid-receiving side.
2. Related Art
In the prior art, there have been a variety of absorbent articles including a sanitary napkin, a urine absorbing pad and a disposable diaper. These absorbent articles are demanded, when worn, for absorbing the liquid waste reliably in liquid absorbent layers so that the liquid waste may not leak to the outside of the absorbent articles. For this purpose, there is an absorbent article which is provided on the surface of the liquid-receiving side with leakage preventing sidewalls extending longitudinally on the two widthwise sides.
In the general structure of the leakage preventing side walls of the prior art, a longitudinally extending unstretchable hydrophobic sheet is joined onto the top sheet of the absorbent article, and an elastic member extending longitudinally of the absorbent article is joined to the hydrophobic sheet. By the elastic shrinking force in the longitudinal direction of the elastic member, a curving force in the longitudinal direction is applied to the absorbent article, and the leakage preventing side walls are raised to the liquid-receiving side of the absorbent article so that the menstrual blood or the like may be prevented from leaking sideways.
In most of the leakage preventing side walls disposed in the absorbent article of the prior art, the elastic members are joined to the hydrophobic sheet while being extended generally in parallel with the liquid-receiving side surface of the absorbent article. When the absorbent article is worn on the crotch of a wearer, therefore, the leakage preventing side walls are indefinite whether they fall outward or inward in widthwise direction. While the absorbent article is worn, therefore, it frequently occurs that the leakage preventing side walls fall down inward in the widthwise direction of the absorbent article.
When the absorbent article is actually worn on the crotch of the wearer, the widthwise midway portion of the absorbent article is frequently deformed to bulge toward the skin of the wearer. If the leakage preventing side walls are fallen inward in the widthwise direction in such a deformed state, they are kept falling down while being in contact with the liquid-receiving side surface of the absorbent article, so that they scarcely restore their outward positions.
As a result, the leakage preventing side walls cannot function as the walls literally, so that the menstrual blood or urine given to the liquid-receiving surface of the absorbent article can not be stopped by the leakage preventing side walls, resulting in that the sideway leakage easily occurs to the sides of the absorbent article. When the leakage preventing side walls fall down inward in the widthwise direction, on the other hand, they cover the absorbing surface of the absorbent article so that the area of the region to contribute to the absorption of the liquid is restricted in the absorbent article.
In the absorbent article of the prior art, on the other hand, the elastic members disposed in the Leakage preventing side walls are extended in the longitudinal direction generally in parallel with the liquid-receiving side surface of the absorbent article. When the absorbent article is curved to conform to the front and rear shapes of the crotch, therefore, the leakage preventing side walls extending in the longitudinal direction are difficult to follow the shapes of the crotch. Therefore, the elastic members positioned at the longitudinal midway portion of the absorbent article abut excessively strongly against the crotch or the perineal portion so that the wearer easily feels a physical disorder.
The present invention has an object to provide an absorbent article in which leakage preventing side walls, when worn on the crotch of a wearer, can be easily directed outwardly in the widthwise direction so as to prevent sideway leakage of a liquid and also to prevent reduction in the substantial area of an absorbent region.
Another object of the invention is to provide an absorbent article in which leakage preventing side walls, when the absorbent article is worn on the crotch of a wearer and curved in accordance with the front and rear shapes of the crotch, can easily conform to the shapes of the crotch so as to prevent the leakage preventing side walls from giving a physical disorder to the wearer.
According to a first aspect of the invention, there is provided an absorbent article comprising: a main body including a support sheet, a liquid absorbent layer laid on the support sheet, and a liquid-permeable sheet covering the liquid absorbent layer; and leakage preventing side walls extending in the longitudinal direction of the main body and lying opposite one another in the widthwise direction of the main body, each leakage preventing side wall having a raised portion which is joined at a root end onto a liquid-receiving side surface of the main body and raised therefrom to have a free end positioned apart from the liquid-receiving side surface, wherein each leakage preventing side wall is provided with first elastically shrinking means for applying an elastic shrinking force along a shrinking action line approaching the free end from the root end as it extends from the two longitudinal end positions of the raised portion of the leakage preventing side wall toward the longitudinally midway position of the leakage preventing side wall.
In the above, when the leakage preventing side walls receives the pressure from the skin wearing the absorbent article, they are easily subjected to a force to bring them down outwardly in the widthwise direction. When the widthwise midway portion of the absorbent article is deformed to bulge toward the skin, therefore, the leakage preventing side walls easily contact with the skin to prevent the sideway leakage effectively. Since the leakage preventing side walls hardly fall down inwardly, moreover, the substantial absorbing area of the liquid-receiving side surface is hardly reduced.
According to a second aspect of the invention, there is provided an absorbent article comprising: a main body including a support sheet, a liquid absorbent layer laid on the support sheet, and a liquid-permeable sheet covering the liquid absorbent layer; and leakage preventing side walls extending in the longitudinal direction of the main body and lying opposite one another in the widthwise direction of the main body, each leakage preventing side wall having a raised portion which is joined at a root end onto a liquid-receiving side surface of the main body and raised therefrom to have a free end positioned apart from the liquid-receiving side surface, wherein each leakage preventing side wall is provided with first elastically shrinking means for applying an elastic shrinking force along a shrinking action line approaching the root end from the free end as it extends from the two longitudinal end positions of the raised portion of the leakage preventing side wall toward the longitudinally midway position of the leakage preventing side wall.
In the above, when the absorbent article is worn on the crotch of a wearer""s body, the leakage preventing side walls are easily deformed to conform to the front and rear curved shapes of the crotch to improve their contact with the skin. Moreover, the leakage preventing side walls can be prevented from abutting excessively strongly against the perineal region or the like.
In the above absorbent articles according to the first and second aspects of the invention, it is preferred that the shrinking action line is curved outwardly or inwardly as it extends toward the longitudinally midway position. However, the shrinking action line may extend generally into such a V-shape that it is folded at the longitudinally midway position to have two strictly or generally straight line portions extending therefrom.
Preferably, the leakage preventing side wall is provided with second elastically shrinking means for applying an elastic shrinking force in the longitudinal direction along the free end. However, it may be possible that elastically shrinking means is not disposed at the free end.
Preferably, the leakage preventing side wall has front and rear end portions longitudinally outwardly of the raised portion, and the front and rear end portions are folded substantially flat and joined onto the main body with the free end being directed outwardly in the widthwise direction.
It may be possible that the leakage preventing side wall is provided with third elastically shrinking means for applying an elastic shrinking force in the longitudinal direction, the third elastically shrinking means being located between the shrinking action line and the root end, that the leakage preventing side wall has front and rear end portions longitudinally outwardly of the raised portion, and that the front and rear end portions are folded substantially flat and joined onto the main body with the free end and the portion having the third elastically shrinking means being directed outwardly in the widthwise direction.
If the front and rear end portions of the leakage preventing side walls are thus folded with the free ends being directed outwardly in the widthwise direction, the free ends of the raised portions of the leakage preventing side walls can be easily directed outwardly in the widthwise direction. When the absorbent article is worn, therefore, the raised portions of the leakage preventing side walls easily fall down outwardly in the widthwise direction and easily come into close contact with the wearer""s skin at the portions between the shrinking action lines and the free ends.
It is possible that the individual elastically shrinking means are each formed by attaching a linear or band-shaped elastic member to a side wall sheet forming the leakage preventing side wall. In this case, a single elastic member may be provided to extend continuously, or a plurality of elastic members may be provided at an interval. Alternatively, the side wall sheet forming the leakage preventing side wall may be provided in itself with an elastically shrinking function to form the individual shrinking action lines. For example, the elastically shrinking means may be formed by forming folding lines (or creases) along the curved shrinking action lines in the side wall sheet exhibiting the shrinkability in the longitudinal direction or by stitching elastic members for forming the shrinking action lines in the nonstretchable side wall sheet.